Thorgalaeg
Deity
It is fun as in movies/games ships always arrive to solar systems in the ecliptic plane. A reflection of our 2-D mind proper of terrestrial mammals.
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Thorgalaeg
Deity
No necessarily in a sci-fi scenery where ships usually have infinite amount of delta-v and thrust power.
warpus
Sommerswerd asked me to change this
That's basically what I assumed, more or less, but I guess I figured that it wouldn't be random, much like planets in a solar system all more or less form on the same plane. Crazy we are 63 degrees off, I wouldn't have expected that!
Makes sense though, thanks, I can throw my story idea out the window now
Thorgalaeg
Deity
You only have to look at the sky at night to know we are totally off the plane of the galaxy. If we were on it, you couldnt see almost nothing of the milky way in Canada since it would be under the horizon or barely over it.
EDIT: wait, is that correct?
EDIT: wait, is that correct?
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warpus
Sommerswerd asked me to change this
That does make sense to me. Each time I'm in a remote part of the world I look up at night, and the way you see the milky way wouldn't make sense if we were parallel to the galactic plane. Or at least I think it wouldn't? The Incans for example used to think of the milky way as a river, almost perpendicular to the horizon. I think you are right that this wouldn't be possible if we were parallel to the plane
No, that would be the case only if Earth's axis was perpendicular to ecliptic plane too.You only have to look at the sky at night to know we are totally off the plane of the galaxy. If we were on it, you couldnt see almost nothing of the milky way in Canada since it would be under the horizon or barely over it.
EDIT: wait, is that correct?
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Thorgalaeg
Deity
OK, just checked it, Earth tilt angle is 23 degrees. So we would see the milky way 23º above the horizon at most, not near the zenit as we see it sometimes (63+23 = 86º):
warpus
Sommerswerd asked me to change this
Now I'm confused about all this again, but that just means it'll be a motivator to read up on it a bit more when I have some time
I forgot to mention that it also depends on your latitude. From equator, you'd still be able to see it near zenith.
Thorgalaeg
Deity
Yes, but we were in Canada with warpus.
hobbsyoyo
Deity
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You only have to look at the sky at night to know we are totally off the plane of the galaxy. If we were on it, you couldnt see almost nothing of the milky way in Canada since it would be under the horizon or barely over it.
EDIT: wait, is that correct?
That's not Warpus's original question as I understand it though. He was asking how the ecliptic planes of the stars in the galaxy are inclined, not how their orbits about the galaxy are inclined, which is different. It's the difference between how Earth's equator is inclined relative to the ecliptic versus how it's orbit is inclined to the ecliptic. The former is ~23degrees, the latter is close to zero.
Thorgalaeg
Deity
But afaik orbit, ecliptic plane and planet rotation are related and usually close. With some exception as Uranus.
hobbsyoyo
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But apparently they aren't that related when it comes to the orbit of a star about the galaxy and how its ecliptic is inclined relative to its orbit about the galaxy which is what I thought Warpus was asking about. But yeah, within solar systems these things are related and usually tightly coupled.
Just found formal definition of ecliptic plane out of curiosity - it's actually not quite the same as the Solar system plane! Didn't know this.
By definition it is the Earth orbit's plane and it's inclined by ~1 degree to the Solar system plane (which can be considered as weighted average of all planets orbits)
Orbits of other planets are within 6 degrees of inclination to it.
warpus
Sommerswerd asked me to change this
Yeah basically I wanted to know if it would be reasonable that ships approaching solar systems in our galaxy would be usually approaching "from the side" or it would be pretty much random in terms of the direction you could expect travellers to come from. Ignoring fuel concerns
Even if the planes of all stellar systems were all aligned, I would still expect travelers to come from unrelated directions. You would only expect travelers to come within the galactic plane, if they came directly from a star far away. If interstellar travel ever happens, I expect it to usually take the form of star hopping, which would involve ships going from star to star and refuel or at least get a gravity assist from each of the stars. The path from the nearest stars to the solar system is not in the plane of the galaxy (as a look into the night sky will confirm), so I would put the highest likelihood of travelers arriving in their general direction instead of the galaxy plane.
warpus
Sommerswerd asked me to change this
That all makes sense, thanks!
Might there be a benefit to approaching solar systems "from the side" in an effort to use the gravitational pull of the outer planets to get closer to the inner planets? I suppose that's probably situation specific
Might there be a benefit to approaching solar systems "from the side" in an effort to use the gravitational pull of the outer planets to get closer to the inner planets? I suppose that's probably situation specific
Yes, probably. I suspect that most efficient way to get at the inner planets is to approach in plane and then use gravity assists to lower your orbital energy relative to the star. Since you need to get rid of your velocity perpendicular to the orbital plane of that system, anyway, I don't see a reason not to approach the system in its orbital plane. Except for time constraints: The most efficient way could take way too long and if you have a lot of fuel to burn, a perpendicular approach might be much faster.
Thorgalaeg
Deity
Changing direction at mid course to arrive in the ecliptic plane would probably consume much more fuel than a direct approach, gravity assist benefit being mostly insignificant in comparison. So the most efficient way would be direct approach imo, using the destination star gravity to change course in the last moment and align the trajectory with the ecliptic plane and then use the planets gravity to help stop the ship. A cosmic carambola.
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